Generator repair

What usually goes wrong

Battery failure tops the list. After that come low oil shutdowns, clogged air filters, worn spark plugs, controller errors, fuel pressure problems and transfer switch faults. Nests and debris in the enclosure cause their share of calls. After flooding, water damage to wiring and controls is a concern.

Before the technician arrives

Collect a few details:

• Brand, model and serial number from the data plate
• Fault code or warning shown on the controller
• What happens: no start, starts then stops, or runs without powering the house
• Last service date and any recent outages
• Any flooding or storm damage near the unit

What not to do

Do not open the unit to work on the engine, wiring or fuel line. A standby generator is wired to your electrical service and connected to gas or propane. If you smell gas, leave the area and call 911 or the gas utility. If the generator was under water, do not try to start it; have it inspected first.

Repair or replace

Most faults are worth repairing. Replacement makes sense when the unit is old, a major engine part has failed, parts are hard to find, or the house now needs more power than the generator can supply. A good technician lays out both options with prices. A replacement may reuse the pad, gas line and transfer switch if they are in good shape. See standby generator installation.

Preventing the next failure

Regular service catches most of these problems early. See generator maintenance.

During an outage

If the generator fails in the middle of a storm, keep the household safe first. Use flashlights rather than candles, keep freezer and refrigerator doors closed, and move to a warm place if the heat is out for long. If you use a portable generator while waiting for the repair, run it outdoors only, far from windows and doors, and never in a garage. Repair visits may take longer to schedule after a big storm, so it helps to report the problem as soon as you notice it.

Questions homeowners ask